This attempts to hack around window-deactivation events we get as a
result of window-manager shortcuts (e.g. increase/decrease volume).
It takes advantage of the fact that window-manager shortcuts are not
exposed to us. If that ever gets fixed, we can presumably modify this
hack.

Also remove ROLE_LIST from the list of form field roles. We had that in
place for when Firefox neglected to use the correct role for listboxes.
Since that Firefox bug is fixed, we no longer need this hack.